CPES vs. PEG

[Kristian]

CPES vs. polyethylene glycol
Any thoughts? I'm concerned about penetration depth on solid, most likely wet, wood.

[Kristian]

CPES vs. polyethylene glycol
Any thoughts? I'm concerned about penetration depth on solid, most likely wet, wood.

[Kristian]

CPES vs. polyethylene glycol
Any thoughts? I'm concerned about penetration depth on solid, most likely wet, wood.

[thechemist]

It depends.

There is the issue of what different products will do, and then there is the issue of what your purpose may be in wood treatment of one sort or another.

Polyethylene glycol [PEG] is commonly used by archaeologists who don't want to do anyting irreversible to an old piece of wood, but want to keep it from getting worse, and "stabilize" it. Being much less volatile than water, it can maintain wood at about the flexibility of damp wood, but without the "drying-out" issue. It will not glue wood fibers back together once deterioration has separated them, and thus does nothing for the strength of wood. Being water-soluble, it can be leached back out of the wood by sufficient water immersion. Thus, it is a reversible treatment.

Penetration depth depends on open porosity, as well as viscosity and time. Since the water present keeps the doors inside the hollow fibers open, it can reasonably be assumed that it will go anywhere a hollow fiber goes, as well as any open porosity between cells. I doubt it will diffuse across a cellulose wall, but it is more likely to, than CPES, in my opinion.

It will penetrate faster if the wood is nearly waterlogged, well above the fiber-saturation point [FSP], since it is water-soluble but much more viscous than water and excess water aids penetration by diffusion and capillary action.

CPES, on the other hand, is an irreversible treatment. The resin system chemically cures, and glues some of the wood microstructure back together. Thus, it restores some physical properties, as the tests at www.woodrestoration.com (http://www.woodrestoration.com) show.

Its depth of penetration depends on open wood porosity. I doubt it will go across a cellulose cell wall, and it seems to me those tests show it does not. Whether it can dissolve enough water to penetrate through the hollow fibers of wood, near the fiber-saturation-point, with the excess water keeping those trap doors open, That is an interesting question and I know of no such tests done, nor any specific data. The referenced penetration experiments experiments were all made , I surmise, on wood well below the fiber-saturation point. It is not clear, but I infer the wood specimens photographed for the penetration tests were all stabilized at room ambient conditions.

So, CPES will likely penetrate better in wood around or below the FSP, due to its much lower viscosity and apparent surfactant properties. That statement may not be true, for some geometries and times. CPES has some pot life, as it is a chemically curing system. Its behavior is also affected by temperature, containing as it does volatile solvents. PEG does not have these limitations, and could slowly and insidiously wick into something over a month, whereas CPES is likely limited to some hours or tens of hours.

Since wood can usually be dried with little effort to somewhat below FSP, unless it is part of a boat in the water, I am moved to ask what exactly are you doing?

[thechemist]

It depends.

There is the issue of what different products will do, and then there is the issue of what your purpose may be in wood treatment of one sort or another.

Polyethylene glycol [PEG] is commonly used by archaeologists who don't want to do anyting irreversible to an old piece of wood, but want to keep it from getting worse, and "stabilize" it. Being much less volatile than water, it can maintain wood at about the flexibility of damp wood, but without the "drying-out" issue. It will not glue wood fibers back together once deterioration has separated them, and thus does nothing for the strength of wood. Being water-soluble, it can be leached back out of the wood by sufficient water immersion. Thus, it is a reversible treatment.

Penetration depth depends on open porosity, as well as viscosity and time. Since the water present keeps the doors inside the hollow fibers open, it can reasonably be assumed that it will go anywhere a hollow fiber goes, as well as any open porosity between cells. I doubt it will diffuse across a cellulose wall, but it is more likely to, than CPES, in my opinion.

It will penetrate faster if the wood is nearly waterlogged, well above the fiber-saturation point [FSP], since it is water-soluble but much more viscous than water and excess water aids penetration by diffusion and capillary action.

CPES, on the other hand, is an irreversible treatment. The resin system chemically cures, and glues some of the wood microstructure back together. Thus, it restores some physical properties, as the tests at www.woodrestoration.com (http://www.woodrestoration.com) show.

Its depth of penetration depends on open wood porosity. I doubt it will go across a cellulose cell wall, and it seems to me those tests show it does not. Whether it can dissolve enough water to penetrate through the hollow fibers of wood, near the fiber-saturation-point, with the excess water keeping those trap doors open, That is an interesting question and I know of no such tests done, nor any specific data. The referenced penetration experiments experiments were all made , I surmise, on wood well below the fiber-saturation point. It is not clear, but I infer the wood specimens photographed for the penetration tests were all stabilized at room ambient conditions.

So, CPES will likely penetrate better in wood around or below the FSP, due to its much lower viscosity and apparent surfactant properties. That statement may not be true, for some geometries and times. CPES has some pot life, as it is a chemically curing system. Its behavior is also affected by temperature, containing as it does volatile solvents. PEG does not have these limitations, and could slowly and insidiously wick into something over a month, whereas CPES is likely limited to some hours or tens of hours.

Since wood can usually be dried with little effort to somewhat below FSP, unless it is part of a boat in the water, I am moved to ask what exactly are you doing?

[thechemist]

It depends.

There is the issue of what different products will do, and then there is the issue of what your purpose may be in wood treatment of one sort or another.

Polyethylene glycol [PEG] is commonly used by archaeologists who don't want to do anyting irreversible to an old piece of wood, but want to keep it from getting worse, and "stabilize" it. Being much less volatile than water, it can maintain wood at about the flexibility of damp wood, but without the "drying-out" issue. It will not glue wood fibers back together once deterioration has separated them, and thus does nothing for the strength of wood. Being water-soluble, it can be leached back out of the wood by sufficient water immersion. Thus, it is a reversible treatment.

Penetration depth depends on open porosity, as well as viscosity and time. Since the water present keeps the doors inside the hollow fibers open, it can reasonably be assumed that it will go anywhere a hollow fiber goes, as well as any open porosity between cells. I doubt it will diffuse across a cellulose wall, but it is more likely to, than CPES, in my opinion.

It will penetrate faster if the wood is nearly waterlogged, well above the fiber-saturation point [FSP], since it is water-soluble but much more viscous than water and excess water aids penetration by diffusion and capillary action.

CPES, on the other hand, is an irreversible treatment. The resin system chemically cures, and glues some of the wood microstructure back together. Thus, it restores some physical properties, as the tests at www.woodrestoration.com (http://www.woodrestoration.com) show.

Its depth of penetration depends on open wood porosity. I doubt it will go across a cellulose cell wall, and it seems to me those tests show it does not. Whether it can dissolve enough water to penetrate through the hollow fibers of wood, near the fiber-saturation-point, with the excess water keeping those trap doors open, That is an interesting question and I know of no such tests done, nor any specific data. The referenced penetration experiments experiments were all made , I surmise, on wood well below the fiber-saturation point. It is not clear, but I infer the wood specimens photographed for the penetration tests were all stabilized at room ambient conditions.

So, CPES will likely penetrate better in wood around or below the FSP, due to its much lower viscosity and apparent surfactant properties. That statement may not be true, for some geometries and times. CPES has some pot life, as it is a chemically curing system. Its behavior is also affected by temperature, containing as it does volatile solvents. PEG does not have these limitations, and could slowly and insidiously wick into something over a month, whereas CPES is likely limited to some hours or tens of hours.

Since wood can usually be dried with little effort to somewhat below FSP, unless it is part of a boat in the water, I am moved to ask what exactly are you doing?

[Kristian]

I have a bowl blank that I would like to turn but it is probably too rotted to stay in one piece on the lathe. I'm trying to find "the best of both worlds" product. Something that penetrates deeply and holds the wood together.

PEG is wax based and I was suspicous that it's not quite what I had wanted. I don't want to have the wood fly apart because it has no holding strength like CPES does.

CPES, being epoxy based, I wasn't sure what it's penetration ability was before it cures and seals the wood. esp when the wood is wet. As you said CPES penetrates better when the wood is dry.

In my case the wood will crack and become unturnable if dryed out without a holding compound. (It's only futher use would be BTU's)

In turn for PEG; it will replace the water, but leave the wood as spongy and weak as it already is.

[Kristian]

I have a bowl blank that I would like to turn but it is probably too rotted to stay in one piece on the lathe. I'm trying to find "the best of both worlds" product. Something that penetrates deeply and holds the wood together.

PEG is wax based and I was suspicous that it's not quite what I had wanted. I don't want to have the wood fly apart because it has no holding strength like CPES does.

CPES, being epoxy based, I wasn't sure what it's penetration ability was before it cures and seals the wood. esp when the wood is wet. As you said CPES penetrates better when the wood is dry.

In my case the wood will crack and become unturnable if dryed out without a holding compound. (It's only futher use would be BTU's)

In turn for PEG; it will replace the water, but leave the wood as spongy and weak as it already is.

[Kristian]

I have a bowl blank that I would like to turn but it is probably too rotted to stay in one piece on the lathe. I'm trying to find "the best of both worlds" product. Something that penetrates deeply and holds the wood together.

PEG is wax based and I was suspicous that it's not quite what I had wanted. I don't want to have the wood fly apart because it has no holding strength like CPES does.

CPES, being epoxy based, I wasn't sure what it's penetration ability was before it cures and seals the wood. esp when the wood is wet. As you said CPES penetrates better when the wood is dry.

In my case the wood will crack and become unturnable if dryed out without a holding compound. (It's only futher use would be BTU's)

In turn for PEG; it will replace the water, but leave the wood as spongy and weak as it already is.

[Dale Harvey]

As I'm sure you well know, turning anything unstable is asking for big trouble. While CPES will help to stabilize the wood a bit and make other things stick to it, I think you will also need a "full strength" epoxy over it to gain sufficent structural integrity for even very low speed turning. Call Smith and see if he can reccomend a clear casting epoxy that is compatible with his product.

[Dale Harvey]

As I'm sure you well know, turning anything unstable is asking for big trouble. While CPES will help to stabilize the wood a bit and make other things stick to it, I think you will also need a "full strength" epoxy over it to gain sufficent structural integrity for even very low speed turning. Call Smith and see if he can reccomend a clear casting epoxy that is compatible with his product.

[Dale Harvey]

As I'm sure you well know, turning anything unstable is asking for big trouble. While CPES will help to stabilize the wood a bit and make other things stick to it, I think you will also need a "full strength" epoxy over it to gain sufficent structural integrity for even very low speed turning. Call Smith and see if he can reccomend a clear casting epoxy that is compatible with his product.

[Ron Williamson]

Kristian,
Could you freeze the blank,then turn it?
Treat it afterwards to stabilize.
Just a thought.
R

[Ron Williamson]

Kristian,
Could you freeze the blank,then turn it?
Treat it afterwards to stabilize.
Just a thought.
R

[Ron Williamson]

Kristian,
Could you freeze the blank,then turn it?
Treat it afterwards to stabilize.
Just a thought.
R

[Will]

Highland Hardware ( highlandhardware.com )has a full range of CA (cyanoacrylate) adhesives .I know that some knowledgeable turners are smearing this stuff on punky wood as they turn .It dries to full strength in seconds .

[gert]

CPES is not an adhesive, use it first and then regular epoxy perhaps with a filler.
Wear a dust mask and face sheild. Good luck.

[Will]

Highland Hardware ( highlandhardware.com )has a full range of CA (cyanoacrylate) adhesives .I know that some knowledgeable turners are smearing this stuff on punky wood as they turn .It dries to full strength in seconds .

[gert]

CPES is not an adhesive, use it first and then regular epoxy perhaps with a filler.
Wear a dust mask and face sheild. Good luck.

[Will]

Highland Hardware ( highlandhardware.com )has a full range of CA (cyanoacrylate) adhesives .I know that some knowledgeable turners are smearing this stuff on punky wood as they turn .It dries to full strength in seconds .

[gert]

CPES is not an adhesive, use it first and then regular epoxy perhaps with a filler.
Wear a dust mask and face sheild. Good luck.

[Jamie Hascall]

An interesting sidelight to the use of PEG in underwater archaeology finds, the Swedish ship Vasa which sank in the 1560s and was raised in the 1960's, was totally saturated with PEG and is now on display in a restored state in its own museum. It's truly a must see if you get to Scandinavia. However, in talking with conservators there, it seems that it was virtually impossible to get the PEG to penetrate totally and now the ship is very slowly starting to rot from the inside. So much for the hubris of thinking we can bring entropy to a halt.

Jamie

[Jamie Hascall]

An interesting sidelight to the use of PEG in underwater archaeology finds, the Swedish ship Vasa which sank in the 1560s and was raised in the 1960's, was totally saturated with PEG and is now on display in a restored state in its own museum. It's truly a must see if you get to Scandinavia. However, in talking with conservators there, it seems that it was virtually impossible to get the PEG to penetrate totally and now the ship is very slowly starting to rot from the inside. So much for the hubris of thinking we can bring entropy to a halt.

Jamie

[Jamie Hascall]

An interesting sidelight to the use of PEG in underwater archaeology finds, the Swedish ship Vasa which sank in the 1560s and was raised in the 1960's, was totally saturated with PEG and is now on display in a restored state in its own museum. It's truly a must see if you get to Scandinavia. However, in talking with conservators there, it seems that it was virtually impossible to get the PEG to penetrate totally and now the ship is very slowly starting to rot from the inside. So much for the hubris of thinking we can bring entropy to a halt.

Jamie

[thechemist]

Originally posted by Jamie Hascall:
<snip>
However, in talking with conservators there, it seems that it was virtually impossible to get the PEG to penetrate totally and now the ship is very slowly starting to rot from the inside. <snip>


Interesting. Did they presume PEG stops fungal rot and assumed no penetration because fungal rot was happening, or did they actually take core samples and assay for PEG and find none whilst verifying the rot to be fungal in origin, or does PEG actually cause some slow, long-term decomposition of wood that they mistake for fungal rot when actually it was PEG-rot, or is it actually bacterial rot from a species of bacteria which eats wood as well as PEG?

You oughta go ask them.

[thechemist]

Originally posted by Jamie Hascall:
<snip>
However, in talking with conservators there, it seems that it was virtually impossible to get the PEG to penetrate totally and now the ship is very slowly starting to rot from the inside. <snip>


Interesting. Did they presume PEG stops fungal rot and assumed no penetration because fungal rot was happening, or did they actually take core samples and assay for PEG and find none whilst verifying the rot to be fungal in origin, or does PEG actually cause some slow, long-term decomposition of wood that they mistake for fungal rot when actually it was PEG-rot, or is it actually bacterial rot from a species of bacteria which eats wood as well as PEG?

You oughta go ask them.

[thechemist]

Originally posted by Jamie Hascall:
<snip>
However, in talking with conservators there, it seems that it was virtually impossible to get the PEG to penetrate totally and now the ship is very slowly starting to rot from the inside. <snip>


Interesting. Did they presume PEG stops fungal rot and assumed no penetration because fungal rot was happening, or did they actually take core samples and assay for PEG and find none whilst verifying the rot to be fungal in origin, or does PEG actually cause some slow, long-term decomposition of wood that they mistake for fungal rot when actually it was PEG-rot, or is it actually bacterial rot from a species of bacteria which eats wood as well as PEG?

You oughta go ask them.

[imported_Ola Sylwan]

Chemist,
if you are really intrested in what is happening with our old ship Vasa you can find more information at: http://www.vasamuseet.se/index.html
It is not rot but acids in the wood that is the problem.
Ola

[imported_Ola Sylwan]

Chemist,
if you are really intrested in what is happening with our old ship Vasa you can find more information at: http://www.vasamuseet.se/index.html
It is not rot but acids in the wood that is the problem.
Ola

[imported_Ola Sylwan]

Chemist,
if you are really intrested in what is happening with our old ship Vasa you can find more information at: http://www.vasamuseet.se/index.html
It is not rot but acids in the wood that is the problem.
Ola

[Tonyr]

Kristian.

Here is a method that has worked for me (once). It is not cheap or easy, and not foolproof. Worth doing only for a special object, probably less than about 12" in the largest dimension.

1. Get some low viscosity slow-setting epoxy, the cheaper the better, since you will need a surplus of the stuff.

2. Immerse the blank in the mixed liquid, within a container only just big enough for it. Weigh the blank down with a floating cover so it is immersed.

3. Put the container in the reservoir of an air compressor (which obviously has to have an easily removable lid), and bring the whole up to pressure (I use 100 psi).

4. Cycle every 5 or 10 minutes or so between ambient and your chosen pressure for as long as you have patience and can trust the epoxy not to set up. This really pumps the epoxy in deep. How deep? Sorry "it depends", but in spalted and/or rotten wood, you should get pretty complete injection, with certainty through any coarse checks.

5. Remove, let drain, bring blank to temperature so epoxy sets. Find a use for the surplus epoxy (got a good boat handy??).

6. When set, mount on face plate and turn.

Good luck.

Tony.

[Tonyr]

Kristian.

Here is a method that has worked for me (once). It is not cheap or easy, and not foolproof. Worth doing only for a special object, probably less than about 12" in the largest dimension.

1. Get some low viscosity slow-setting epoxy, the cheaper the better, since you will need a surplus of the stuff.

2. Immerse the blank in the mixed liquid, within a container only just big enough for it. Weigh the blank down with a floating cover so it is immersed.

3. Put the container in the reservoir of an air compressor (which obviously has to have an easily removable lid), and bring the whole up to pressure (I use 100 psi).

4. Cycle every 5 or 10 minutes or so between ambient and your chosen pressure for as long as you have patience and can trust the epoxy not to set up. This really pumps the epoxy in deep. How deep? Sorry "it depends", but in spalted and/or rotten wood, you should get pretty complete injection, with certainty through any coarse checks.

5. Remove, let drain, bring blank to temperature so epoxy sets. Find a use for the surplus epoxy (got a good boat handy??).

6. When set, mount on face plate and turn.

Good luck.

Tony.

[Tonyr]

Kristian.

Here is a method that has worked for me (once). It is not cheap or easy, and not foolproof. Worth doing only for a special object, probably less than about 12" in the largest dimension.

1. Get some low viscosity slow-setting epoxy, the cheaper the better, since you will need a surplus of the stuff.

2. Immerse the blank in the mixed liquid, within a container only just big enough for it. Weigh the blank down with a floating cover so it is immersed.

3. Put the container in the reservoir of an air compressor (which obviously has to have an easily removable lid), and bring the whole up to pressure (I use 100 psi).

4. Cycle every 5 or 10 minutes or so between ambient and your chosen pressure for as long as you have patience and can trust the epoxy not to set up. This really pumps the epoxy in deep. How deep? Sorry "it depends", but in spalted and/or rotten wood, you should get pretty complete injection, with certainty through any coarse checks.

5. Remove, let drain, bring blank to temperature so epoxy sets. Find a use for the surplus epoxy (got a good boat handy??).

6. When set, mount on face plate and turn.

Good luck.

Tony.

[Tom Lathrop]

This question will probably get much more informed answers if asked of Fine Woodworking or one of the woodworking forums. They have shown some truly amazing turned pieces that looked as if they might fall apart sitting still, much less being turned on a lathe.

The people I know who use PEG use it to keep green wood from cracking while drying and not to prevent rot, which it probably will not do.

Tony,

Your example sounds very interesting. How much did you dilute the epoxy? Could you see a positive effect of the pressure cycling versus constant pressure?

[Tom Lathrop]

This question will probably get much more informed answers if asked of Fine Woodworking or one of the woodworking forums. They have shown some truly amazing turned pieces that looked as if they might fall apart sitting still, much less being turned on a lathe.

The people I know who use PEG use it to keep green wood from cracking while drying and not to prevent rot, which it probably will not do.

Tony,

Your example sounds very interesting. How much did you dilute the epoxy? Could you see a positive effect of the pressure cycling versus constant pressure?

[Tom Lathrop]

This question will probably get much more informed answers if asked of Fine Woodworking or one of the woodworking forums. They have shown some truly amazing turned pieces that looked as if they might fall apart sitting still, much less being turned on a lathe.

The people I know who use PEG use it to keep green wood from cracking while drying and not to prevent rot, which it probably will not do.

Tony,

Your example sounds very interesting. How much did you dilute the epoxy? Could you see a positive effect of the pressure cycling versus constant pressure?

[Tonyr]

I used just plain epoxy, which as I recollect I cooled somewhat before beginning the impregnation. Since I was unsure of set-up time (because of the possible exotherm reaction and its uncertainties) I cycled up and down several times over about an hour. I did not dare just leave it in there under pressure.

Today I would not use this method at all, on mature reflection. I think I would slow down the turning speed to (say) a few revs/min, and use an angle grinder with King Arthur(??) "chain saw" cutter to rough it out, then use a Norton flexible abrasive depressed centre disc to finish off to final dimension. This way, you never have to risk running the (defective) workpiece at a dangerous speed.

This certainly works (have done it or similar methods many times), but puts constraints on the shapes of the finished product, compared with using standard turning tools. You can sometimes use a router instead of the angle grinder for the initial roughing out, but with even more shape constraint.

After all this, if you really need epoxy impregnation of the completed piece this is perhaps best done by simple repetition of surface flooding. Personally, I would just leave it as finished, or better still soak it in a bath of 50/50% wax and walnut oil (at about 150 to 200 degrees F) for an hour or two. This is cheap, effective, food safe, but does nothing for strength. It is a finish I use all the time for cheese boards when I have a piece of wood with really special figure.

Regards, Tony.

[Tonyr]

I used just plain epoxy, which as I recollect I cooled somewhat before beginning the impregnation. Since I was unsure of set-up time (because of the possible exotherm reaction and its uncertainties) I cycled up and down several times over about an hour. I did not dare just leave it in there under pressure.

Today I would not use this method at all, on mature reflection. I think I would slow down the turning speed to (say) a few revs/min, and use an angle grinder with King Arthur(??) "chain saw" cutter to rough it out, then use a Norton flexible abrasive depressed centre disc to finish off to final dimension. This way, you never have to risk running the (defective) workpiece at a dangerous speed.

This certainly works (have done it or similar methods many times), but puts constraints on the shapes of the finished product, compared with using standard turning tools. You can sometimes use a router instead of the angle grinder for the initial roughing out, but with even more shape constraint.

After all this, if you really need epoxy impregnation of the completed piece this is perhaps best done by simple repetition of surface flooding. Personally, I would just leave it as finished, or better still soak it in a bath of 50/50% wax and walnut oil (at about 150 to 200 degrees F) for an hour or two. This is cheap, effective, food safe, but does nothing for strength. It is a finish I use all the time for cheese boards when I have a piece of wood with really special figure.

Regards, Tony.

[Tonyr]

I used just plain epoxy, which as I recollect I cooled somewhat before beginning the impregnation. Since I was unsure of set-up time (because of the possible exotherm reaction and its uncertainties) I cycled up and down several times over about an hour. I did not dare just leave it in there under pressure.

Today I would not use this method at all, on mature reflection. I think I would slow down the turning speed to (say) a few revs/min, and use an angle grinder with King Arthur(??) "chain saw" cutter to rough it out, then use a Norton flexible abrasive depressed centre disc to finish off to final dimension. This way, you never have to risk running the (defective) workpiece at a dangerous speed.

This certainly works (have done it or similar methods many times), but puts constraints on the shapes of the finished product, compared with using standard turning tools. You can sometimes use a router instead of the angle grinder for the initial roughing out, but with even more shape constraint.

After all this, if you really need epoxy impregnation of the completed piece this is perhaps best done by simple repetition of surface flooding. Personally, I would just leave it as finished, or better still soak it in a bath of 50/50% wax and walnut oil (at about 150 to 200 degrees F) for an hour or two. This is cheap, effective, food safe, but does nothing for strength. It is a finish I use all the time for cheese boards when I have a piece of wood with really special figure.

Regards, Tony.